Falling, not osteoporosis, is the strongest risk factor for rib fracture
Professor Barrett-Connor and her colleagues are to be acknowledged
for their carefully-conducted epidemiologic risk factor study on rib
fractures of elderly men, an important but sparsely studied subject.
However, we are not happy with their conclusions and policy implications.
In this 6-year prospective cohort study among 5879 community dwelling
older men Barrett-Connor et al. (1) observed that independent risk factors
for an incident rib fracture (n=126) were history of rib fracture, lower
hip bone mineral density (BMD), age 80 or older, and difficulty with
instrumental activities of daily living (IADL) (all measured at baseline).
They also found that men with a history of rib fracture (n=860) had at
least a twofold increased risk of future fracture of the rib, wrist, or
hip, independent of BMD and other covariates. Additionally the authors
reported the circumstances leading to rib fracture. They observed that
only four out of the 126 incident rib fractures (3%) occurred in the
absence of trauma; the great majority of these fractures (90 cases, 71%)
followed a fall.
For an unknown reason, the circumstances leading to rib fracture (ie,
in most cases falling) were not included in the fracture prediction models
of the authors, although falling preceding the fracture, not osteoporosis,
is the strongest ever known single risk factor for a fracture of an older
adult (2,3). Instead, the authors highlighted in their conclusions that
rib fractures should be considered osteoporotic fractures in the
evaluation of older men for treatment to prevent future fracture. This
was because rib fracture was associated with old age, lowered hip BMD, and
history of fracture, which in turn are, according to the authors, classic
risk markers of osteoporosis. In the Discussion, the authors suggested
even more frankly that rib fracture is due to osteoporosis and the
treatment of this condition means bone specific drugs.
However, the above noted conclusions and policy implications
favouring osteoporosis pharmacotherapy do not withstand scientific
scrutiny. First, in the study of Barrett-Connor et al. (1) lowered hip
BMD was a moderate-level risk factor for rib fracture only (hazard ratio
1.43 per 1SD decrease in hip BMD). Second, inclusion or exclusion of hip
BMD in the multivariate adjusted models of risk factors for rib fracture
had rather marginal effect on the above noted clinical risk factors.
Third, in the multivariate models for history of rib fracture at baseline
as a predictor of new fractures, inclusion of BMD in these models
attenuated the risk very little, by less than 4%. Together these
observations were clear signs that lowered BMD is not a strong independent
risk factor for rib fractures and that the clinical risk factors (high
age, difficulty with IADL, and history of rib fracture) operate mostly via
falling, not via osteoporosis.
Another important point concerns the bone status of the studied men.
Table 1 shows that not even men who received incident rib fracture during
the 6-year follow-up were osteoporotic at baseline (1). Their mean hip
BMD t-score was -0.94, which is far above the WHO criteria of osteoporosis
(t-score < -2.5). In fact, an average man in this study did not even
fulfil the criteria of less severe condition or osteopenia (t-score
between -1.0 and -2.5). Thus, older men without osteoporosis cannot be a
good target group for osteoporosis medication. And this is even before
one considers that there is absolutely no evidence of efficacy,
effectiveness, or cost-effectiveness of treatment in prevention of any
type of men’s fractures by bone specific drugs.
In short, osteoporosis itself is not really the issue, it is
fractures of older adults that matter. And when examining this issue more
deeply, one realises that falling, not osteoporosis, is the strongest
single risk factor for fractures. In other words, in great majority of
elderly patients falling is the true direct cause of the fracture (2,3).
According to the less highlighted finding of Barrett-Connor et al. (1),
this seems to be the case in men’s rib fractures, too.
For all these reason, we argued strongly in our recent BMJ paper that
the focus in fracture prevention of older adults should be shifted from
osteoporosis to falls (2). This should be a fascinating option to
politicians and health care providers, because current evidence indicates
that falls can be prevented – even cost-effectively (3-6).
Pekka Kannus, MD, PhD
Injury and Osteoporosis Research Center, UKK-Institute, Tampere, Finland
Teppo LN Järvinen, MD, PhD
Department of Surgery, University and University Hospital of Tampere,
1 Barrett-Connor E, Nielson CM, Orwoll E, Bauer DC, Cauley JA.
Epidemiology of rib fractures in older men: Osteoporotic Fractures in Men
(MrOS) prospective cohort study. BMJ 2010;340:c1069.
2 Järvinen TL, Sievänen H, Khan KM, Heinonen A, Kannus P. Shifting
the focus in fracture prevention from osteoporosis to falls. BMJ.
3 Kannus P, Sievanen H, Palvanen M, Järvinen T, Parkkari J.
Prevention of falls and consequent injuries in elderly people. Lancet
4 Gillespie LD, Robertson MC, Gillespie WJ, Lamb SE, Gates S,
Cumming RG et al. Interventions for preventing falls in older people
living in the community. Cochrane Database Syst Rev 2009;Issue 2:CD007146.
5 Davis JC, Robertson MC, Ashe MC, Liu-Ambrose T, Khan KM, Marra
CA. Does a home-based strength and balance programme in people aged >
80 years provide the best value for money to prevent falls? A systematic
review of economic evaluations of falls prevention interventions. Br J
Sports Med 2010;44:80-9.
6 Kemmler W, von Stengel S, Engelke K, Häberle L, Kalender WA.
Exercise effects on bone mineral density, falls, coronary risk factors,
and health care cots in older women. The randomized controlled senior
fitness and prevention (SEFIP) study. Arch Intern Med 2010;170:179-85.
Competing interests: No competing interests